Last night, The New York Timesrevealed the identities of the people who secretly hoisted two bleached-out American flags atop the Brooklyn Bridge on July 22. The self-styled art installation by Matthias Wermke and Mischa Leinkauf set off a police investigation and security fears in the media, but the two Berliners say they intended the flags as an avant-garde birthday tribute to the bridge’s German-born engineer, John Roebling.

“Few people would care if we did the same thing in Berlin,” Leinkauf told the Times. “Of course, we did not have the same problems with terrorism.”

Wermke and Leinkauf are performance artists who use cities as their canvas. Their work is often illegal, but in their home country (and elsewhere) it hasn’t provoked the sort of consternation seen in New York over the last few weeks.

Here are some highlights:

They rode a handmade go-cart through the Berlin subway

They climbed smokestacks in Prague

They scaled skyscrapers in Tokyo

(wermke-leinkauf.com)

They did a handstand on a statue that tops a church in Heilbronn, Germany

(wermke-leinkauf.com)

They swung on a homemade swing suspended from buildings in Berlin

They squeegeed the windshields of subway and tram cars

They installed a bunch of flags on landmarks in Vienna

They attached balloons to the Brooklyn and Manhattan Bridges—and nobody noticed

(Valentina Powers/Flickr)

In 2007, the duo staged what now looks like a dry run for their flag action, attaching strings of balloons to New York’s Manhattan and Brooklyn Bridges. Unlike now, there were no terrorism fears stoked by the press, no police investigations, no subpoenas of Twitter parody accounts, just a couple of nice photos on Flickr. Was the 2007 installation a dangerous example of a city caught unaware, or was the response to the flag episode seven years later overblown? Draw your own conclusions.